The science fiction comedy follows four suburban men - played by Ben Stiller, Vince Vaughn, Richard Ayoade and Jonah Hill - who join forces to form a neighbourhood watch group.
When they discover their town is being overrun by aliens, they take action to protect the planet from extermination.
The new cilp, released by Yahoo, shows the quartet on a stakeout.
The film is directed by Lonely Island member Akiva Schaffer from a script by Seth Rogen and Evan Goldberg. Its international trailer was released earlier this week.
The Watch opens in US cinemas on July 27 and August 29 in the UK. Watch a trailer below:
